travel in Zambia

We are travelling in our won vehicle through Zambia in June 2005. We will be entering Zambia from Malawi at Chilanga and will spend a few days in South Luangwa at Flatdogs camp. From here we will drive to Lusaka (a long drive). Can anyone tell me what the road is like these days and if there are any good campsites along the way as I think we might not make it in one day.
From Lusaka we are travelling to Kafue National Park - what's the road like here? It was grim in 1998 but I understand it has been resurfaced - is this true?